Spray gun for producing a fan-like pattern

ABSTRACT

A spray gun is disclosed herein a plurality of spray nozzles are assembled in one unit, aligned with each other and placed relatively close together. The unit includes a rectangular body having a row of orifices formed in at least one of the longer sides thereof. These orifices communicate with a chamber formed by a groove carved in the adjacent long side of side of body. Spaced from each open end of the orifices is force-fitted a bead or small bushing. From the same side of the body containing the groove, a row of bores are drilled so that they communicate with respective ones of the orifices in the region between the bushing and the opening of the orifices. A plate is disposed against the groove of the body, and has formed thereon a pair of grooves each on opposite sides running the length thereof. The groove in the body is coupled to a pressurized air supply through suitable passageways in the body and the groove in the plate adjacent the body is coupled to a liquid supply, through other suitable passageways in the body. Another row of bores couples the groove on one side of the plate to the groove on the other side. An additional row of bores are drilled through the plate and each bore is aligned with a respective one of the bores in the body. Finally, in the plate, another row of bores is drilled from the side of the plate normal to the other bores therein and communicating with respective ones of the bores aligned with the bores in the body and communicating with the groove on the side of the plate, opposite the body. Suitable plugs are placed in the ends of these last mentioned bores. Another plurality of bores are drilled in the body opposite and aligned with respective ones of the other bores therein, with means in these other bores to control the opening of each one of the respective bores.

United States atent I [191 Hudson Dec.3,1974

[76] Inventor: Truman 0. Hudson, 3205 Oakwood, Lynwood, Calif. 90262 22Filed: Feb. 28, 1974 21 Appl. No.: 446,720

[52] US. Cl 239/407, 164/267, 239/417.5, 239/428.5, 239/434, 239/557,239/562, 239/566 [51] Int. Cl. B22d 17/22 [58] Field of Search 239/186,266, 268, 407,

444, 536, 548,550, 551,556, 557,562, 566, 581; 164/158, 267; 425/96,DIG. 50

Primary Examiner-Lloyd L. King Assistant Examiner-Andres KashnikowAttorney, Agent, or FirmDominick Nardelli [57] ABSTRACT A spray gun isdisclosed herein a plurality of spray nozzles are assembled in one unit,aligned with each other and placed relatively close together. The unitincludes a rectangular body having a row of orifices formed in at leastone of the longer sides thereof. These orifices communicate with achamber formed by a groove carved in'the adjacent long side of side ofbody. Spaced from each open end of the orifices is force-fitted a beador small bushing. From the same side of the body containing the groove,a row of bores are drilled so that'they communicate with respective onesof the orifices in the region between the bushing and the opening of theorifices. A plate is disposed against the groove of the body, and hasformed thereon a pair of grooves each on opposite sides running thelength thereof. The groove in the body is coupled to a pressurized airsupply through suitable passageways in the body and the groove in theplate adjacent the body is coupled to a liquid supply, through othersuitable passageways in the body. Another row of bores couples thegroove on one side of the plate to the groove on the other side. Anadditional row of bores are drilled through the plate and each bore isaligned with a respective one of the bores in the body. Finally, in theplate, another row of bores is drilled from the side of the plate normalto the other bores therein and communicating with respective ones of thebores aligned with the bores in the body and com- I municating with thegroove on the side of the plate,

opposite the body. Suitable plugs are placed in the ends of these lastmentioned bores. Another plurality of bores are drilled in the bodyopposite and aligned with respective ones of the other bores therein,with means in these other bores to control the opening of each one ofthe respective bores.

11 Claims, 8 Drawing Figures FIELD OF THE INVENTION BACKGROUND OF THEINVENTION Single orifice spray heads for spray guns are simple toconstruct and can be made to produce many types of spray pattern. Forexample, to produce a round pattern, a round orifice is utilized; toproduce a long rectangular or oval pattern, an oval orifice is utilized,etc. However, as everyone knows, the density of the liquid particlesvaries across the spray pattern wherein the density is greater at thegeometric center. Therefore, in an elongated spray pattern, one finds amuch wider variation of density than in the circular pattern. Normallythis variation in density is of no consequence because the operator,being a skilled human, can handle and move the spray gun as he sees fitto produce a uniform coating. The problem arises when the spray gun isto move automatically. In such automatic operations the spray gun ismade to move along a straight line, as any other motion provided theretowould be costly and still one cannot be assured the motions of a humanoperator are reproduced. This drawback is multiplied if the article tobe coated uniformly is relatively large in relation to the spraypattern. Large articles to be coated with a liquid lubricant are usuallyfound in 'die casting operations. In such operations the prior artteaches that the dies can be brush-coated. For-example, US. Pat. No.3,248,762 teaches the useof a wide brush with bristles on oppositesides, wherein the brush automatically moved down after the dies open toapply lubricant on the faces of both dies. This procedure operates verywell provided there are no deep recesses in the dies wherein the brushbristles cannot reach. However, everyone knows that a spray willpenetrate mo st recesses and, as mentioned above, the-spray should havesubstantially uniform coating characteristics.

OBJECTS OF' THE INVENTION 7 An object of this invention is to provide asimple and rugged spray gun that produces an elongated spray pattern ofsubstantially uniform density. I

Another object of this invention is to provide a spray gun with aplurality of aligned orifices wherein each orifice has the capability ofatomizing and discharging liq-.

uid droplets.

Another object of this invention is to provide a spray gun for coatingautomatically die casting dies while producing a substantially uniformcoating, thereby increasing cycle speed.

Another object of this invention is to provide a spray gun with aplurality of aligned orifices wherein the discharge range from eachorifice can be independently adjusted while still allowing the spray gunto be started or stopped by one automatic trigger means.

Another object of this invention is to provide a multiorifice spray gunthat is capable of blasting air along,

or a combination of air and liquid droplets.

These and other objects and features of advantage will become moreapparent after studying the following description of the preferredembodiment of this invention, together with the appended drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a side schematic elevationof a die casting machine incorporating an automatically controlled dielubricant applier, incorporating my novel spray gun.

FIG. 2 is a front elevation of the die lubricant applier of FIG. 1.

FIG. 3 is an exploded pictorial view of the spray gun shown in FIGS. 1and 2.

FIG. 4 is an enlarged partial front elevation of the spray gun inpartial section. I I

FIG. 5 is a view in partial section taken on line 55 in FIG. 4 in thedirection of the arrows.

FIG. 6 is a view in partial section taken on line 6-6 of FIG. 4 in thedirection of the arrows.

FIG. 7 is a view taken on line 7-7 in FIG/4. in the direction of thearrows.

FIG. 8 is an enlarged side elevation of the spray gun, in partialsection.

DETAILED DESCRIPTION OF THE DRAWINGS Referring to FIG. 1 wherein astandard die casting machine is shown schematically, the machine has afixed die 11 suitably mounted to a fixed frame 12, and also has amoveable die 13 mounted on a ram 14. On

frame 12 is mounted a fixture 15, more clearly shown in FIG. 2. Thefixture has a horizontal shelf 16 extending over' the space between thespread-apart dies 11 and 13. Spaced from and above shelf 16 is anothershelf shown) are connected to the cylinder 18 to cause the 3 piston 19to extend (lower) from and to retract (raise) into the cylinder 18. Upto now, the description has been of standard items and form no part ofmy invention except for my novel spray gun 21. Suitable controls lowermy spray gun 21 automatically between the spaced dies, as taught forexample in US. Pat. No. 3,248,762.

Referring to FIG. 3, my spray gun 21 has a rectangu-. lar body 25 towhich are attached a pair of tubes 23 and 24 disposed parallel to piston19. The tubes 23 and 24 have threaded ends and are threaded intosuitable threaded holes in the body 25, as illustrated by threaded hole26 (FIG. 4) to which tube 23 is threaded. Locking nuts 27 and 28 locktubes 23 and 24, respectively to body 21. The tubes 23 and 24'extendfreely through suitable holes, not shown, in shelf 16. The top ends oftubes 23 and 24 are coupled together by a plate 29 (FIG. 2), for.obvious reasons, and have flexible lines 31 and 32 coupled,respectively, to tubes 23 and 24.

' Suitable springs 33 are mounted on opposite sides of screws, as shownby screws 37 in FIG. 4, holds the body 25 and plates 35 and 36 together.

The spray gun 21 has a plurality of spray orifices 41 formed in the body25, and are disposed in two rows on opposite sides thereof with, forexample, spray orifices 41 in a row. More or less spray orifices can beplaced in a row and because of the teachings of my invention, they canbe placed as close as one-half inch apart, but in the embodiment shown,the spray orifices are separated apart, for example, one and one-halfinches. On each orifice 21 is ejected a fine mist of liquid droplets andair, and the combination is of substan' tially uniform characteristics.Liquid is fed to the body 25 through tubes 43 and 44 (FIG. 3) disposedconcentric within respective tubes 23 and 24. Air is fed into the body25 through tubes 23 and 24. The manner in which the air and liquid isducted through the body 25 and passageway plates 35 to insure that afine spray 'mist of liquid droplets is discharged through each sprayorifice 41 will now be described.

Referring particularly to FIGS. 4, 5, 6, and 7, the details describedfor concentric tubes 23 and 43 will hold for concentric tubes 24 and 44.As seen in FIG. 4, tube 23 communicates with hole 26, which is formed bydrilling a blind hole in body 25. On the bottom of hole 26 is formed amale thread 45, to which is attached tube 43 by a suitable tubing nut46. Coaxial with hole 26 is drilled a smaller hole 47. On the oppositeside of the body is counterbored a well 48, for reasons that will beexplained hereinafter. On the face of the body 25, making contact withplate 35, are milled 3 aligned grooves, of which only two grooves, 49and 50, are shown, in FIGS. 4 and 5. As shown therein, these grooves areseparated in the region between the blind hole 26, for reasons that willbecome apparent hereinafter. These grooves are made to communicate withrespective blind holes 26, by drilling suitable holes 51. Now air canenter the grooves from hole 26. As shown in FIG. 8, the sprayorifices41' are holes drilled into thebody 25 to communicate withrespective grooves 49 or 50.

Within orifices 41 are pressed suitable beads or small bushings 54, toform a constriction therein for reasons that will become apparent. Eachbushing 54 is spaced a predetermined distance from the outer ends, andthese distances are preferably equal to each other. Because'of theVenturi effect produced as the air leaves 5 bushing 54, a drop inpressure will be observed in the regions immediately following thebushing.

l have devised an arrangement of ducts in the spray head 21 to insurethat a substantially equal quantity of liquid flows to each of theserespective low-pressure regions. From the same side of the body 25wherein grooves 49 and 50 are formed, holes 56 are drilled tocommunicate with the respective orifice 41 in this lowpressure region,i.e., between the bushing and the outer edge. Now, referring to FIGS. 6and 7, holes 57 are drilled through plate 35 and each hole 57 is alignedwith the respective hole 56 in the body. Liquid is supplied to holes 56and 57 from tubes 43 or 44, as follows: Plate 35 has a pair of bores,such as bore 58, drilled therethrough and in alignment withcounter-bored well 48. On the face of the plate 35, adjacent to body 25,are

milled a pair of parallel grooves 61, each disposed and spaced from therespective row of holes 57, as shown in FIG. 7. Another groove 62 isformed that extends from hole 58 to the middle of one groove 61 and in asimilar manner a partially shown groove 63 is formed to extend from theother hole, not shown, similar to hole 58 to the middle of the othergroove 61.

As shown in FIG. 6, on the opposite side of plate 35 are milled anotherpair of parallel grooves 65, spaced slightly inboard of the pair ofgrooves 61 on the opposite side. One groove 61 is made to communicatewith one respective groove 65 by drilling a plurality of holes 66through the plate. These holes 66 are offset with re spect to grooves 61and also with respect to groove 65, for reasons that will be explainedhereinafter. The other groove 61 is made to communicate with the otherrespective groove 65, also by drilling a plurality of holes 67 throughplate 35. These holes 67 are also offset with respect to both grooves 61and 65. As shown in FIG. 8, each hole 57 is made to communicate withrespective groove 65 by drilling a hole 69 from the side of plate 35, sothat hole 69 is spaced from the face of plate 35 for reasons that willbe explained. The portion of each hole 69, between hole 57 and the sideof the plate, is suitably plugged with a dowel 70.

The spray gun operates as follows: When piston 18 is programmed to lowerthe gun 21 between the spray dies 11 and 13, a limit switch turns on anair valve (both not shown) and pressurized air enters tubes 23 and 24,passes through holes 51 into grooves 49 and 50, and out of orifices 41.As air exits each bushing 54, liquid is drawn up holes 56 and the liquidis atomized. The liquid arrives to each hole 56 by respective holes 57and 69, grooves 65, holes 67, grooves 61 and 62, and aligned holes 58,48, and 47. Within the liquid passageways, and in particular each hole48, there is provided a one-way valve in a form of a ball 72 and spring73. This prevents liquid from dripping after the air supply is shut off.By allowing the liquid from one tube 43 to feed liquid to only theorifices on one side, and the liquid from the other tube 44 to feedliquid to only the orifices on the other side, different liquids can beused on respective sides. Also, one side can be shut off while the otherside is usable, Groove 62 communicates with the center of one groove 61,and insures equal amounts of liquid going into both ends thereof. Theholes 66 and 67, being offset, insures a more equal distribution ofliquid in respective grooves 65, which, in turn, insures a more evendistribution at each orifice.

Although all the above precautions have been taken to insure asubstantially uniform spray between each orifice, due to inherentmanufacturing tolerances, the spray, for some applications, is notsufficiently uniform. I have devised a means to adjust the rate ofliquiddrop lets exiting each orifice 41 that does not require substantiallyclean liquid. This system only requires the liquid, free of dirtparticles above a given size, as determined by the cross-section of therespective passageways already described, for the liquid to flowthrough. Any reduced restrictions in these liquid passageways, ofcourse, requires cleaner fluids. The means for adjusting the sprayincludes a plurality of bores formed in a body 25, such as bore 74, asshown in FIG. 8, each of which bores is aligned substantially with arespective hole 56. These bores 74 communicate also with thelow-pressure regions immediately following the bushing 54. Each bore 74is formed with a shoulder 75 by drilling a counterbore 76 and providingtherein threads. Within the threaded counterbore 76 is screwed aneedle-valve 77 whose pointed end seats against the shoulder. Anotherbore 78 is drilled in body 75 to communicate with bore 76, as shown inFIG. 8.

A similar means is provided for each orifice 41, thus by simply turningthe needle-valve 77, the amount of air entering each orifice 41 throughrespective bore 74 is controllable. Since this air is controllable, theliquid entering the orifices 41 from the holes 56 below is also beingcontrolled, and if a dust particle does enter the system, the means isself-cleaning by simply opening the needle-valve 77 and resetting it.

Having described the preferred embodiment of my invention, one skilledin the art, after studying the above disclosure, can devise otherembodiments and still come within the spirit of my invention. Therefore,my invention is not to be considered as limited to the describedembodiment, but includes all embodiments coming within the scope of theclaims.

I claim:

1. A spray gun comprising:

a body having a plurality of orifices formed therein;

said body having first duct means communicating with each orifice;

first means for supplying pressurized air to said first duct means-sothat air passes through each of said orifices and exists said body;

a bushing having a central aperture disposed within each one of saidorifices, spaced inward from the opening thereof so that a Venturieffect is produced by the air passing therethrough;

said body having a second duct means communicating with each orifice inthe region between said bushing and the opening thereof;

second means for supplying liquid to-said second duct means so that theliquid therein mixes with the air passing through each of said bushingsin each of said orifices.

2. The spray gun of claim 1 wherein:

said body has a plurality of third duct means connecting the respectiveregions between said bushings and the opening of said orifices to theatmosphere; and

valve means in each of said third duct'means to regulate the flow ofatmospheric air to'each one of said respective regions.

3.The spray gun of claim 1 wherein:

said body is shaped as an elongated, rectangular block, and saidorificesare disposed aligned on at least one of the elongated sides thereof;

said first duct means includes a first groove formed in another one ofthe elongated sides of said body, adjacent the side with said orifices,and said orifices extending between said groove and the outside of saidbody;

said second duct means comprising a passageway plate disposed againstthe side of said body having said first groove;

said passageway plate having a second groove extending the lengththereof;

said body having a plurality of holes, each disposed at right angles tosaid respective orifices and communicating with said second groove.

4. The spray gun of claim 3 wherein:

said passageway plate has a third groove extending the length thereof,and disposed on the opposite side from said second groove;

said passageway plate has a plurality of first holes drilledtherethrough, to communicate with said second groove and said thirdgroove;

said third groove is disposed against said body;

said passageway plate has a plurality of second holes drilledtherethrough, and aligned with respective ones of said holes in saidbody;

said passageway plate has a plurality of holes formed between saidsecond groove'and aligned with respective ones of said second holesdisposed at right angles thereto.

5. The spray gun of claim 4 wherein:

said body has also a second plurality of aligned orifices disposedopposite said first mentioned orifices;

said second plurality of orifices also extending between said groove andsaid body, and the outside thereof;

said passageway plate has a fourth groove formed on F the same side ofsaid second groove, and disposed substantially parallel thereto;

said body has another plurality of holes, each disposed at right anglesto respective ones-of said second plurality of orifices andcommunicating with said fourth groove.

6. The spray gun of claim 5 wherein:

said passageway plate has a fifth groove formed on the same side of saidthird groove, and disposed substantially parallel thereto;

said passageway plate has a plurality of holes drilled therethrough toconnect said fourth groove to said fifth groove;

said passageway plate has a plurality of third holes drilledtherethrough and aligned with the respective ones of said otherplurality of holes in said body, which holes communicate with saidsecond plurality of orifices;

said passageway plate has a plurality of holes formed between saidfourth groove and with respective ones of said holes in communicationwith said second orifices.

7. The spray gun of claim 5 wherein:

said body has a plurality of third duct means communicating withrespective regions between said bush- "ing and the opening of saidorifices, and communicating with the atmosphere; and valve means in eachone of said duct means to regulate the flow of atmospheric air to eachone of said respective regions.

8. A multi-orifice spray gun' comprising:

a body havinga plurality of orifices formed therein and first duct meansfor supplying pressurized air to each of said orifices;

each of said orifices being shaped so that a Venturi effect is producedby the air passing therethrough;

second duct means carried by said body;

said second duct means having a main duct and a plurality of minor ductsbranching therefrom;

means for supplying liquid into said main duct, each of said minor ductsterminating and communicating with a respective orifice in the lowerpressure region as produced by the Venturi effect.

9. The gun of claim 8 wherein:

said body is shaped as an elongated, rectangular block, and saidorifices are disposed in a line on at least one of the elongated sidesthereof.

10. The gun of claim 8 wherein:

each of said orifices includes a cylindrical bore having a largerdiameter at its exterior opening, a smaller diameter spaced inward fromthe opening thereof. a

11. The gun of claim 10 wherein:

a bushing is disposed in each of said orifices to form the smallerdiameter thereof.

1. A spray gun comprising: a body having a plurality of orifices formedtherein; said body having first duct means communicating with eachorifice; first means for supplying pressurized air to said first ductmeans so that air passes through each of said orifices and exists saidbody; a bushing having a central aperture disposed within each one ofsaid orifices, spaced inward from the opening thereof so that a Venturieffect is produced by the air passing therethrough; said body having asecond duct means communicating with each orifice in the region betweensaid bushing and the opening thereof; second means for supplying liquidto said second duct means so that the liquid therein mixes with the airpassing through each of said bushings in each of said orifices.
 2. Thespray gun of claim 1 wherein: said body has a plurality of third ductmeans connecting the respective regions between said bushings and theopening of said orifices to the atmosphere; and valve means in each ofsaid third duct means to regulate the flow of atmospheric air to eachone of said respective regions.
 3. The spray gun of claim 1 wherein:said body is shaped as an elongated, rectangular block, and saidorifices are disposed aligned on at least one of the elongated sidesthereof; said first duct means includes a first groove formed in anotherone of the elongated sides of said body, adjacent the side with saidorifices, and said orifices extending between said groove and theoutside of said body; said second duct means comprising a passagewayplate disposed against the side of said body having said first groove;said passageway plate having a second groove extending the lengththereof; said body having a plurality of holes, each disposed at rightangles to said respective orifices and communicating with said secondgroove.
 4. The spray gun of claim 3 wherein: said passageway plate has athird groove extending the length thereof, and disposed on the oppositeside from said second groove; said passageway plate has a plurality offirst holes drilled therethrough, to communicate with said second grooveand said third groove; said third groove is disposed against said body;said passageway plate has a plurality of second holes drilledtherethrough, and aligned with respective ones of said holes in saidbody; said passageway plate has a plurality of holes formed between saidsecond groove and aligned with respective ones of said second holesdisposed at right angles thereto.
 5. The spray gun of claim 4 wherein:said body has also a second plurality of aligned orifices disposedopposite said first mentioned orifices; said second plurality oforifices also extending between said groove and said body, and theoutside thereof; said passageway plate has a fourth groove formed on thesame side of said second groove, and disposed substantially parallelthereto; said body has another plurality of holes, each disposed atright angles to respective ones of saiD second plurality of orifices andcommunicating with said fourth groove.
 6. The spray gun of claim 5wherein: said passageway plate has a fifth groove formed on the sameside of said third groove, and disposed substantially parallel thereto;said passageway plate has a plurality of holes drilled therethrough toconnect said fourth groove to said fifth groove; said passageway platehas a plurality of third holes drilled therethrough and aligned with therespective ones of said other plurality of holes in said body, whichholes communicate with said second plurality of orifices; saidpassageway plate has a plurality of holes formed between said fourthgroove and with respective ones of said holes in communication with saidsecond orifices.
 7. The spray gun of claim 5 wherein: said body has aplurality of third duct means communicating with respective regionsbetween said bushing and the opening of said orifices, and communicatingwith the atmosphere; and valve means in each one of said duct means toregulate the flow of atmospheric air to each one of said respectiveregions.
 8. A multi-orifice spray gun comprising: a body having aplurality of orifices formed therein and first duct means for supplyingpressurized air to each of said orifices; each of said orifices beingshaped so that a Venturi effect is produced by the air passingtherethrough; second duct means carried by said body; said second ductmeans having a main duct and a plurality of minor ducts branchingtherefrom; means for supplying liquid into said main duct, each of saidminor ducts terminating and communicating with a respective orifice inthe lower pressure region as produced by the Venturi effect.
 9. The gunof claim 8 wherein: said body is shaped as an elongated, rectangularblock, and said orifices are disposed in a line on at least one of theelongated sides thereof.
 10. The gun of claim 8 wherein: each of saidorifices includes a cylindrical bore having a larger diameter at itsexterior opening, a smaller diameter spaced inward from the openingthereof.
 11. The gun of claim 10 wherein: a bushing is disposed in eachof said orifices to form the smaller diameter thereof.